{"id":"CVE-2021-40647","aliases":["DEBIAN-CVE-2021-40647","EUVD-2021-27821","GHSA-p3mv-74p6-4mgc","MGASA-2025-0097","UBUNTU-CVE-2021-40647"],"status":"published","title":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter...","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","severity":{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.00337,"percentile":0.27291,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-20","CWE-787"],"published":"2022-09-09T17:57:28Z","modified":"2026-10-23T18:03:33Z","fixes":[{"ecosystem":"Debian:13","package":"man2html","fixed_in":["1.6g-16"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"man2html","fixed_in":["1.6g-16"],"sources":["osv"]},{"ecosystem":"Mageia:9","package":"man2html","fixed_in":["1.6-6.1.mga9"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-14","1.6g-15","1.6g-16"]},{"source":"osv","ecosystem":"Debian:13","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6g-16"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6g-16"}]}]},{"source":"osv","ecosystem":"Mageia:9","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6-6.1.mga9"}]}]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-7","1.6g-8"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-9","1.6g-9ubuntu1","1.6g-11"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-12"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-14"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-14","1.6g-15","1.6g-16"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-16"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-16build1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"man2html","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6g-16","1.6g-16build1"]}],"products":[{"vendor":"man2html_project","product":"man2html"}],"references":[{"url":"https://gist.github.com/untaman/cb58123fe89fc65e3984165db5d40933","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-40647"},{"url":"http://man2html.com"},{"url":"http://na.com"},{"url":"https://github.com/advisories/GHSA-p3mv-74p6-4mgc"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-40647","tags":["advisory"]},{"url":"https://advisories.mageia.org/MGASA-2025-0097.html","tags":["advisory"]},{"url":"https://bugs.mageia.org/show_bug.cgi?id=34072","tags":["report"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/BAS4Z6KUDJQV22DP5BTQX56WVFT3FF32/","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2021-40647","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-40647","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-40647","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-09T17:57:28Z","modified":"2024-08-04T02:51:06.37Z","updated_at":"2026-11-02T14:33:01.495293Z"}],"euvd":[{"id":"EUVD-2021-27821","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-09T17:57:28Z","modified":"2024-08-04T02:51:06Z","updated_at":"2026-11-03T03:24:19.692229Z"}],"ghsa":[{"id":"GHSA-p3mv-74p6-4mgc","title":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter...","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-10T00:00:25Z","modified":"2023-02-01T05:08:39Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-20"],"updated_at":"2026-11-02T14:50:49.403077Z"}],"nvd":[{"id":"CVE-2021-40647","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-09T18:15:09.197Z","modified":"2026-06-17T04:07:12.84Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:07:06.906968Z"}],"osv":[{"id":"CVE-2021-40647","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-09T18:15:09.197Z","modified":"2026-04-16T04:41:47.702832778Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:21.249056Z"},{"id":"DEBIAN-CVE-2021-40647","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-09T18:15:09.197Z","modified":"2026-10-23T18:03:33.15641911Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:35.521549Z"},{"id":"UBUNTU-CVE-2021-40647","description":"In man2html 1.6g, a specific string being read in from a file will overwrite the size parameter in the top chunk of the heap. This at least causes the program to segmentation abort if the heap size parameter isn't aligned correctly. In version before GLIBC version 2.29 and aligned correctly, it allows arbitrary write anywhere in the programs memory.","status":"published","published":"2022-09-09T18:15:00Z","modified":"2026-10-17T12:56:20.736431079Z","cvss":[{"version":"3.1","score":5.5,"vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:29.220315Z"},{"id":"MGASA-2025-0097","title":"Updated man2html packages fix security vulnerability","description":"In man2html 1.6g, a specific string being read in from a file will\noverwrite the size parameter in the top chunk of the heap. This at least\ncauses the program to segmentation abort if the heap size parameter\nisn't aligned correctly. In versions before GLIBC version 2.29 and\nif aligned correctly, it allows arbitrary writes anywhere in the program's\nmemory.\n","status":"published","published":"2025-03-15T01:40:42Z","modified":"2026-04-16T04:41:08.340269289Z","updated_at":"2026-11-02T15:49:43.178336Z"}]}}